Field of the Invention
The present invention relates generally to an electromechanical system for continuously infusing medication into a patient, and more particularly to a single system capable of supplying a plurality of different medications which are to be simultaneously infused into a patient, with the system also being capable of providing a printed record detailing the actual performance of the system over a period of time.
In the past there have been two techniques used to deliver drugs which may not be orally ingested to a patient. The first such technique is through an injection, or shot, which delivers a large dosage at relatively infrequent intervals to the patient. This technique is not always satisfactory, particularly when the drug being administered is potentially lethal or has negative side effects when delivered in a large dosage. This problem results in smaller injections being given at more frequent intervals.
Alternatively, the second technique involves administering a continuous flow of medication to the patient through an IV bottle. Medication may also be delivered through an IV system with an injection being made into a complex maze of IV tubes, hoses, and other paraphernalia. As an alternative to these two techniques of administering medication to a patient, the recent addition of medication infusion pumps has come as a welcome improvement.
Infusion pumps are utilized to administer drugs to a patient in small, metered doses at frequent intervals or, alternatively, in the case of some devices, at a low but essentially continuous rate. Infusion pump therapy may be electronically controlled to deliver precise, metered doses at exactly determined intervals, thereby providing a beneficial gradual infusion of medication to the patient. In this manner, the infusion pump is able to mimic the natural process whereby chemical balances are maintained precisely by operating on a continuous time basis.
Such infusion pumps may use as a power source a battery, which may be either contained inside the main housing of the system, or, alternatively, made integrally as a part of a disposable cassette which includes the actual pump used to precisely meter the amount of medication supplied The combination pump/battery cassette is disclosed in U.S. Pat. No. 4,808,167 entitled "Medication Infusion System With Disposable Pump/Battery Cassette," which was filed simultaneously with this application, is assigned to the assignee of this application, and is hereby incorporated herein by reference. Battery-powered pumps generally use the battery as the power source for the electrical or electronic components used to control the infusion system in addition to using the battery to power the motor or other apparatus used to pump the medication being infused.
Since the portion of the pump through which medication is pumped must be sterile, in most applications of infusion equipment some portion of the equipment must be used only once and then disposed of, typically at regular intervals such as once daily. The pump portion of the infusion pump device is generally the disposable portion, typically designed to be a disposable cassette of inexpensive design, which is easily installable onto the main housing of the system.
One of the problems of existing drug infusion systems is the sheer bulk of such systems, particularly in the case where the patient must have several substances infused. Such systems are useful only to infuse a single medication, so several complete systems must be used. It will be recognized that the bulk of such systems will generally substantially impair the mobility of the patient, often forcing an otherwise ambulatory patient to become bedridden.
In addition, most hospitals have shown substantial resistance to purchasing such systems, since a single patient may require several complete systems As a result, the IV has remained the principal method for infusing medications in hospitals. It is therefore apparent that it would be desirable to provide a medication infusion system which would be capable of infusing a plurality of medical fluids, and this is a primary objective of the present invention.
Presently nurses must maintain a record of medication infused into a patient, whether the medication is infused by an IV or by an infusion system. Such manual record keeping is tedious and subject to error, either in recording of in reading after the initial figures are recorded It is apparent that it is desirable to maintain a written record of medication infused, and it is thus an objective of the present invention to provide for automatic generation of such a written record when desired.
It is also desirable to retain a simple design to minimize the cost of construction both of the system and of the disposable cassette, and to accomplish all these objects in a manner which will retain all of the advantages of reliability, durability, and safety of operation. All the advantages of the present invention will result in a superior medication infusion system having a number of advantages making the system a highly desirable alternative to systems presently available.